Health officials said more people have reported cases of E. coli, as a multi-state outbreak linked to chopped romaine lettuce continues to spread.

The Centers for Disease Control and Prevention said about 53 cases of E. coli have been reported across 16 states, with 18 new cases reported after April 13. Pennsylvania, Idaho, New Jersey and Montana reported the highest number of cases.

The CDC said 31 people have been hospitalized, including five who have developed hemolytic uremic syndrome, a type of kidney failure. No deaths have been reported.

The E. coli outbreak has been linked to romaine lettuce grown in Yuma, Arizona, though no particular brand or grower has been identified. The CDC urged consumers anywhere in the U.S. to throw out any store-bought chopped romaine lettuce, including salads and salad mixes and to try and confirm where romaine lettuce comes from before eating it.

E. coli symptoms typically include diarrhea, stomach cramps and vomiting. Symptoms lasting longer than a week can result in hemolytic uremic syndrome.